Abstract
Background: Deterioration of bone density and quality is of serious concern due to the high incidence of fracture in older individuals. As people age and their level of physical activity decreases, too much bone resorption occurs in relation to formation, resulting in overall loss of bone mass and structural integrity. Bone mineral density (BMD) is used as an indirect indicator of risk of osteoporosis and bone fracture. Both swimming and running have been found to have a positive effect on bone mineral density. A comparison of the effects of swimming and running on bone mineral density in humans has not yet been performed. Objective: The objective of this study was to compare the effects of running and swimming on bone mineral density in young individuals versus mature individuals and to compare intrinsic variables of body weight, height, gender, years swimming or running, distance ran or swam per week, and hours of physical activity per week. Design: This was a quantitative, correlational study that sought to determine whether statistically significant differences in bone mineral density exist between swimmers and runners across the lifespan. Methods: This study included 54 total participants with 12 runners under age 30, 18 runners over age 30, 11 swimmers under age 30, and 13 swimmers over age 30. Heel bone mineral density of each participant was assessed using the GE Achilles Ultrasonometer. Results: No statistically significant difference in bone mineral density existed between swimmers and runners in the young adult or mature adult groups (P = 0.618). Athlete weight was the only factor that had statistically significant differences in bone mineral density. The results do not indicate that the mode of activity (swimming/running) correlates with significantly different findings in BMD. Limitations: The small sample size may decrease statistical power and the ability to generalize these findings to the populations. The degree of causality cannot be determined due to the study’s correlational nature. The mature population who participates in these activities may act as a confounding variable due to their unique characteristics. Conclusions: No correlation between mode of activity and bone mineral density can be established at this time. The results demonstrate that swimming and running have similar effects on bone density. Athlete weight had statistically significant differences in bone mineral density. This indicates that the overall body weight plays a larger role in the formation/maintenance of bone mineral density than activity selection.